Telegraph system



Patented Mar. 31, 1925.

UNITED STAT-ES PATENT 021 )?!e s.

GEORGE o. CUMMINGS, or ORANGE, new JERSEY, as ienos TO wnsiriirtn n i'ioTRIc COMPANY, r co figure, or'i inwi'ronxjim menace-Ara SYSTEM.

a lication filed September 7, 1922; Serial No. ssaeam I windings lO-and '13. In order that the zit-matures of these relays may be biased,

To all whom it may concern:

Be it known that I, Gnonen C. CUMMING a subject of the King of Great Britain, residing at Orange,- in the county of Essen State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a clear, concise, and .exactfdescription.

This invention relates to telegraph systems particularly to systems equipped to provide full duplex service, but which are particularly applicable to half dupleiiserv- In accordance with the above and other I objects the present invention provides a pair of polarized relays associated with a line conductor in such a manner that arec'eiving operator may transmit abreak signal to a transmitting operator while the latter operator is in the act of sending. Also these relays function, should the line be opened by both operatorssimultaneously, following the closure offlthe line by either operator, to restore the system to normal thereby permitting either operator to obtain control of the system.

The invention isillustrated in the accoim panyi'ng drawings, in which Fig. 1 shows one embodiment of the invention; While Fig. 2 illustrates modification of thearrangement disclosed in Fig. 1.-

In Fig. 1 of the drawing .are'show'n two terminal stations Xand'Y connected by'a line conductor 5, and the equipment at each station when the system is usedifor half duplex operation. The duplexsets at each 'of-the terminal stations X and Y have four polarized relays arranged differentially; Relays 6' and 7' are line relays, and have serially connected with line conductor. 5 windings '9 and 12- respectively, while: connected lilzewisein t QMiifiO M liM that is; arranged to remain in the position set until asubsequ'ent energization, wind ings 11 and 14 are also provided. These windings are connected through a key 27 either to battery 3'o1r 4, depending upon the characterof the bias, through an adjustable resistance 26. 4 1

A sec'ond pair of relays 15 and 16; also having three windings; are arranged to operate in conjunction with relays 6 and '3.

Relay 15 may beTconsidered a sending".

break relay; whiler'elay 16 maybe termeda transmitting or pole changer relay which applies battery to the "apex of the ratio arms in which the windings 0t relays 6' and 7 are connected, in accordance "withthe message to be transmitted over the line conductor 5 to the terminal'station Y and subsequently over a 'subscri bers circuit 18.- Serially connected with the armature ofre lay 6 are operating windings 20 and 23' of relays 15 i and 16', respectively. "Normally current of sixty milliamperes flows through windings 20. and 23 and the subscribers circuit l-Tiir a direction which tends to hold the arma-" tu-res' of relays 15 16' against themarking (that is,- the'right.hand) contacts. Bat-- teries 3l and 33, positive and negative polarity; respe.ctively,"with their accompanying resistances 28 ,"2'9uand 30', 28 being adjustable, form a potentiometer and normally supply a currentof fifteen inilliam'peres 16', respectively, in a direction tending to move the ,armatures' ;to their spacing (that is, thei-r'left hand) contacts; but this cur rent is not sufiic-ient to overcome the effect of windings 20 and '23-. VVhenev'er the ciricuitof'battery 33'is opened due to .the-separationjof'the' armature of relay? from'its" right-handcontact, the current" through the windings Y21 and 22 is" reversed sothat it tends to hold the armatures of relays 15 and 16 a-gains't their marking'contactsy'butfit is :not of sutlicient 'value to' moi're'ithem" from their spacing contacts should they l'iappen tofbe'iii engagementwith the latter contacts; .Should the armat'u-res of these relays remain-in engagement wlth their spacing contacts until'thearmature of relay 7 engages -itsV.spacing (that is,- its left-hand) contact, current-passes.through windings 19'and 24E sufficient strength "to cause the restoration of these relays to their marking contacts.

Each of the relays 6 and 7 has connected between its armature and a cooperating contact a condenser 35 and aresistance 36. These elements tend to prevent any slight chattering of the armatures oi? relays 6 and 7, and consequent disruption of the transmitted signals which might occur due to unbalance and in addition to eliminate the sparking effects at the contacts.

At the terminal station Y there is located equipmentidentical to that just described as being located at terminal station X.

When it is desired to transmit impulses from the circuit 17 associated with station X to the loop circuit 18 associated with station Y, key 25 is operated whereby the battery associated therewith is disconnected from the windings 20 and 23 of relays 15 and 16, so that windings 21 and 22 of these relays move their armatures to the left.

Relay 16 in thus reversing the. position or its armature connects the positive source'o't battery with the apex otthe ratio arms 111 which the windings of relays 6 and 7 are serially connected. An impulse will accordingly be transmitted over the line conductor 5, which traverses the windings 59, 60, 62, 63 of relays 56 and 57 in series, the greaterportion of the current flowing to the negative pole of the battery through the left-hand contactof relay 66. These relays are thereupon caused to move their armatures to'th'e right. Relay- 56 in operating opens at its contact the circuit extending from the battery associated with loop circuit 18 and the windings 70 and 7 3 of relays and 66 for causing the operation of sounder 411, which is, as is well understood by those skilled in the art, connected in operative relation with the'loop circuit'lS.

Sounder 41 will respond in a manner to give an audible representation of? the signal. transmitted from the loop circuit 17 I asso ciated with station X. Relay 57 in moving its armature to the right functions to prevent the reversal of the armatures of relays 65 and 66 by windings 71 and 72 upon the opening of the loop circuit including windings 70 and 73 at the contacts of relay 56. That is, when relay 57 opens its left-hand contact. the negative pole of battery 83 is disconnected from the potentiometer ar-' rangement including resistance 78 and 79,

whereby current-now flows from the posi tive pole of this battery through resistance 79, which is of a larger value than resistance 78, and through the windings 71 and 72 of relays 65 and 66 respectively:

The direction of this current is such as to maintain the armatures in engagement with their marking (that is, their left-hand) contacts. Also when the armature of relay 57 engages its right-hand tact, a circuit is.

completed through windings 69 and 7 1 which tends to aid windings 71 and 7 2.

Should the operator on the circuit 18 desire during the transmission of impulses from the loop circuit 17 to interrupt the sending of such operator, it only becomes necessary that the former operator open the transn'iitting key for removing battery from the conductor. extending to windings 70 and 73 of relays 65 and 66. Accordingly, these relays are caused to move their armatures to the right immediately upon the closure of key 25- which causes the armatures of relays 15 and 16 to move to the right, whereupon relays 56 and 57 move their armatures to the left and establish a condition in which windingsTO and 73 are effective to move their .armatures to the right, the circuit of windings 70 and 7 3 being open at key 75 and the circuit of windings 69 and 7 1 being open at the righthand contact of relay 57. The operating relay 66 causes the connection of the 'positive source of battery with the apex of the ratio arms in which the windings of relays 56 and 57 are included and the transmission of a corresponding impulse over line conductor 5 for likewise causing the reversal of the armatures of relays 6. and 7 and the opening of the circuit 17. Relays 15 and 16 thereupon reverse in a manner identical with that in which, as just de scribed, relays 65 and 66 reversed when relays 56 and 57 reversed. The opening of the loop circuit 17 in this manner communicates to the operator at the station at which the circuit 17 terminates a signal indicative that the receiving operatorfdesires to transmit.

Should the operators at the stations where the circuits 17 and 18 terminate, open their keys simultaneously, relays 15 and 16. and

and Y, respectively. Relay 6 in reversing the position of its armature, opens the loop circuit 18 at station Y. When the armature of relay 7 engages its left-hand contact, the

circuit through windings-19 and 24 is completed, the effect of which. is sufficient 'to restore relays 15 and 16 to the position shown. Likewise, at station. Y, relays 65 and 66 are caused to reverse the position of their armatures to the fmarking contacts.

The reversal of the 'armatures of relays 16 and 66 at stations X and Y, respectively, impresses on the conductor 5 a marking impulse whereby relays 6 and 7, and 56 and .57 at the respective stations reverse the posi circuit 17 while relay 56 likewise opens the p 1,53 1, sec

tion of their armatures. Circuits 1? and 157 are now closed.

Should the operator at the station to which the circuit 17 extends, close key 25 and the operator at station on circuit 18 operate key as in sending, such operator will have obtained command of the circuit and can communicate with the other operator. Likewise. had the operator on. the

circuit 18 closed key 7 prior to the closure In the modification shown in Fig. 2, a line conductor 101 extends between two terminating stations X and Y, where there is located duplex equipment arranged for half duplex service. Each of the terminating; stations X and Y have associated therewith circuit-s 102 and 103 to and from which impulses are repeated. Like the arrangement described in connection with Fig. lra pair otrelays 10 1 and 105 are connected with the end of the conductor 101, which terminates at station X.

Each of these relays is provided with three windings. one set of which is serially connected with the line conductor 101. while another set is serially connected with the artificial line. Likewise, the third set is connected to battery through a switch 106 and an adjustable resistance 107 for normally biasing such relays.

This modification, however, in place of employing a pair of relays having three windings as break and transmitting relays, utilizes a corresponding number of relays. but the number of windings is reduced. Tindings 108 and 109 of relays 110 and 111. respectively. are connected serially with the circuit 102 through the right-hand contact and armature, of relay 104. Also when the circuit is closed at key 113, current of suiticient strength flows through windings 108 and 109 to maintain the relays against their marking; contacts. Also windings 114 and 115 of relays 110 and 111 are connected to resistances 116, which are adjustable, and 117 and battery 118 forming: the elements of a potentiometer. These windings are supplied with current under these conditions in a direction tending to reverse the position of their armatures.

The equipment at station Y is identical to that at station X. like parts being. represented with like reference characters with the prime indices added.

Inasmuch as the operation of the system, except the portion pertaining to the operation when the operators at both stations open their keys sin1ultaneously, isthe sanie as de scribed in connection with Figpl, a detailed description thereof is not. considei ednecessary. The description will there'i' ore, he confined to the operation of the system when both operators open their keys simultaneonsly. The operators on the circuits .102 and 103 in opening their respective keys disconnectsthe battery from the windings of relays 110 and 111 and 1.10 and 111/ at stations X and Y, whereby these relays re verse the position of their iii-matures. A spacing impulse is thereupon transmitted over the line conductor 101 from each of the terminatiirq stations, and therefore relays 10s. and 105, and 10 1 and at stations X and Y, respectively, reverse the positions of their armatures for opening the loop circuits extending to the respective stations. Relay 105 opens at its right-handcontact the circuit extending: from battery 118 through resistances. and windings 1 14; and of relays 110 and 111, respectively.

However. upon the engagementot its ar' mature with the left-hand contact. the batterv which is connected to one terminal of resistance 120 is connected to the nodal point to whichthe battery 1.18 is connected. Upon the reversalof the armatureot relaylllO, the resistance 1.20 is of a much lower value than resistance 117 so that the connection of resistances 120 and 116 in the manner just describedcauses the respective batteries to oppose one another, whereby the current flowing through resistance 117 and the wind inns 114 and 115 of relays 110 and 111 is of sufficient strength to restore these relays to their marking contacts. 7

-Likewise, at station Y relays 110 and 111 are caused to reverse the position of their armatures to the posit-ion shown in the drawing. Now when either oi the operators closes his transmitting key, the other operator may obtain control of the system in a manner similar to that described in connection with Fig. 1. I

Although'the invention has been disclosed as applied to a particular circuit, it is obvious that changes may be made without departing from the spirit of the invention. The invention claimed is: i 1. Incombination, a line extending between two stations, duplex equipment associated with said line. a circuit extending from said line at each of said stations, means for opening andclosing each of said circuits. a break relay and a pole changer relayconnected in each oi. said circuits, and circuit connections for insuring' the restoration, of said relays to normal following, the simulta neous opening of said circuits.

2. In combination, a line extending between two stations, duplex equipment associated with said line, a circuit extending from said line ateach of said tat n trans mitting means for opening and closing said circuits, a polarized break relay and a polarized pole changer relay connected in each of said circuits, and means for insuring the res toration of said relays to normal following the simultaneous opening of said circuits.

3. In combination, a line extending bctween two stations, duplex equipment connected with said line at each 01? said stations, a circuit extending from said line at each of said stations, transmitting means individual to each of said circuits, a break relay and a. pole changer relay connected in each or said circuits, and means "for permitting the oper ator of either of said transmitting means to obtain control over said relays following the simultaneous transmission of break signals.

i. In combination, circuit, a pole changer relay and a break relay having a plurality of windings, one of the windings oi each of said relays being connected serially to said circuit, a source of current in said circuit of a strength sufficient to maintain said relays in a predetermined position, a second winding on each of said relays, said winding being included in a local circuit, a source of current in said local circuit of a strength tending to reverse the position of said relays, and an additional winding on each, of said relays arranged to aid said second mentioned winding in restoring said relays to normal under predetermined conditions.

In combination, a circuit, a pole changer relay and a break relay having a plurality of windings, one of the windings of each of said relays being connected serially to said circuit, a source or current in said circuit of a strength suiiicient to maintain said relays in a predetermined position, a second Winding on each of said relays, said winding being included in a local circuit, a source of current in said local circuit of a strength tending to reverse the position of said relays, and means included in a local circuit for insuring under predetermined conditions the restoration of said relays to normal. v

6. In combination, a circuit, a pole changer relay and a break relay having a plurality of windings, one of the windings of each of said relays being connected serially to said circuit, source ot'current in said circuit of a strength sutlicient to maintain said relays in a predetermined position, a second winding on each; of said relays, said windings being included in a local circuit, a source of current in said local circuit of a strength tending to reverse the position of said relays.

and means effective under predetermined conditions for supplying to said winding a current of suilicient strength to cause the reversal of said relays from their spacing to their marking contacts.

In witness whereof, I hereunto subscribe my name this 1st day of September, A. D.

GEORGE C. CUMMINGS. 

